1. Field of the Invention
The present invention relates to an ink jet printer in which an ink cartridge is used as an ink reservoir from which ink is supplied for printing, and relates particularly to a mechanism for inserting an ink cartridge to such an ink jet printer.
2. Description of the Related Art
One common mechanism for inserting an ink cartridge to an ink jet printer ("ink cartridge insertion mechanism" below) requires sliding an ink cartridge into position on a holder such that an ink outlet piece in the ink cartridge is pierced though by an ink supply needle disposed in the ink cartridge holder of the ink jet printer.
An ink cartridge insertion mechanism of this type is disclosed in, for example, Japan Unexamined Patent Publication (kokai) H5-16378 (1993-16378), which was also filed by the present inventors. The ink cartridge used with the ink cartridge insertion mechanism disclosed in the cited publication comprises a flexible ink bag filled with ink, an ink outlet piece formed in the ink bag, and a rectangular, rigid plastic case for holding the ink bag. The ink outlet piece of the ink bag is exposed at one side, more specifically at the front end, of the plastic case. The ink cartridge is thus slid horizontally into the ink cartridge holder so that the ink supply needle in the holder is inserted to the ink outlet piece.
When an ink cartridge is not mounted on the holder with this type of ink cartridge insertion mechanism, the ink supply needle is exposed in the opening in the holder through which the ink cartridge is inserted.
A potential problem with this construction, however, is that exposure of the unprotected tip of the ink supply needle can be dangerous because the tip is typically sharp, and can also subject the needle to damage when something is dropped thereon from the insertion opening in the holder.
To prevent the above-noted problems, the above-cited document teaches an ink cartridge insertion mechanism having a shutter disposed to the ink cartridge holder. This shutter opens when an ink cartridge is inserted to the opening, and closes again when the ink cartridge holder is removed such that when the ink cartridge is not installed the shutter isolates and protects the ink supply needle.
Ink jet printers that supply ink from an ink cartridge to the ink jet head after the ink cartridge has been loaded with the ink supply needle on the holder inserted to the ink outlet piece of the cartridge are generally factory tested for normal printer operation by actually loading an ink cartridge and printing. When the printing test is completed, the ink cartridge is removed and printers that have passed the test are then shipped.
It will be obvious that this test method leaves an amount of ink in the ink supply path after the initial printing test. There is thus the possibility that this residual ink will leak from the tip of the ink supply needle during shipping. Such leakage can soil the area around the needle which is not desirable, and this soiling can lead to customer complaints.
There is therefore a need for an ink cartridge insertion mechanism for an ink jet printer whereby residual ink leaked from the ink supply needle when an ink cartridge is not installed can be collected.
There is a further need for an ink cartridge insertion mechanism for an ink jet printer whereby residual ink leaked from the ink supply needle when an ink cartridge is not installed can be collected, and the ink supply needle can also be protected.